The invention refers to a sliding control system with loading control for telescopic shafts to be used in steering columns in motor vehicles. Such telescopic shafts comprise a female member and a male member in the form of tube pieces inserted one within the other. They are provided, at the interface thereof, that is to say the female member inner lateral surface and the male member outer lateral surface, with a number of ribs and longitudinal grooves that mutually engage enabling the rotation of all the mentioned pieces.
The present invention relates to those telescopic systems undergoing longitudinal displacement of one member relative to the another (displacement of the male member relative to the female member), under controllable load conditions which can take place either on actuating the telescopic regulation mechanism when steering wheel height with regard to the driver is desired to be changed or when it is desired to facilitate assembly on the motor vehicle, or finally the shock that the steering system suffers on proving its performance as a security system for the vehicle to which it is fitted.
In order to meet the previous requirements and technical conditions it has been designed that between said male member outer lateral surface and said female member inner lateral surface, both members are provided with longitudinal grooves on the lateral surface thereof. There is also provided a group of rollers fastened through the corresponding sleeves according to the above mentioned technical requirements and operation features.
The system of the present invention provides the above mentioned loading control action at the same time it facilitates taking-up of play between the male and the female members. Furthermore, the relative movement between these members or the adjusted load value that is causing it, will be affected by torque created by rotation to which said male member and female member are subjected.
The invention provides that stress which is necessary for the relative displacement between the two parts of the telescopic shaft is kept constant for any application and along all the displacement path in such a way that the assembly is provided with a certain braking or damping performance to the applied load.
Although the system of the invention has been devised to be used in a direct way, specifically in the steering columns in motor vehicles it is possible to be fitted in other applications due to its simplicity and easy operation.
Regarding the possibility that the system of the invention can be used as a security system for the motor vehicle, this is made possible by the particularity of that system of being able to have a braking or damping performance, either in the extended or in the retracted condition, absorbing the energy liberated in the event of crash, further keeping constant the necessary stress for relative displacement between the members in the telescopic shaft along the displacement path.
In addition, the present invention also provides the possibility to facilitate the correction of the play that usually appears between different tube pieces in the telescopic shafts, thus avoiding the undesirable play producing noise and vibration on running the vehicle. Transferring noise and vibration to the steering wheel and therefore to the user is also avoided as well as it provides a perfect assembly operation.
On the other hand, the conceptual mechanism that is provided takes into consideration the significance of torque which should be applied for rotation of the whole telescopic shaft on the previously mentioned sliding load between the two members with relative displacement. Such mechanism allows to separate, almost completely, this torque from the longitudinal action of the movement caused by the axial load, so that the effect caused by this torque becomes minimum.
The present invention heightens the easiness of assembling. Assembling is carried out by using few auxiliary and accessory elements and, in any case, its great assembling simplicity does not involve that weight and costs become significantly increased as compared to the advantages of the system itself.
Another object of the present invention is to provide a loading control system which is suitable to adjust the stress during the relative displacement between the parts of the telescopic shaft of the steering column. The invention further allows for a good development of the movement by integrally joining all the live parts to one another minimizing the play as well as the influence of the torque related to rotation. It further provides an effective mechanical arrangement which is also simple and cost effective.
Further details and features of the present patent application will be apparent from the following description, which refers to the accompanying drawings that schematically represent the preferred details. These details are given by way of example, which refer to a possible case of practical embodiment, but it is not limited to the details disclosed herein; therefore this description must be considered from an illustrating point of view and without any type of limitations.
A detailed list of the various parts cited in the present patent application is given below: (10) female tube member, (11) male tube member, (12) mouth, (13) longitudinal grooves, (14) fork, (15) longitudinal protrusion, (16) longitudinal protrusion, (17) longitudinal grooves, (18) fork, (19) regulator, (20) head, (21) cylindrical portion, (22) closure, (23) ridges, (24) adjusting element, (25) body, (26) stump, (27) rollers, (28) sleeve.